The present invention relates to method and apparatus for essentially simultaneously emulsifying and feeding alkenyl succinic anhydride (ASA) into a process stream of a papermaking process. ASA is a papermaking additive, which enhances a number of hydrophobic paper properties. Because ASA is insoluble oil, it must be emulsified prior to introduction to a papermaking process. Currently a number of technologies are used to facilitate the emulsion of ASA in papermaking processes.
In order to adequately emulsify ASA for a papermaking process, two requirements must be met. First, the resulting emulsion must impart on the produced paper good sizing properties. Second, the emulsion must also be easily runnable through papermaking machines. One currently known manner of producing ASA emulsifications involves using mechanical emulsion methods but it is not an efficient manner of forming the emulsion.
Furthermore, optimal introduction of ASA into a process stream occurs when there is a rapid mixing of the ASA with other chemicals into the process stream, in the presence precise stoichiometric conditions with minimal water usage and in and optimal residence and contact times with other chemicals. As a result, mixtures containing ASA and other chemicals should be introduced after the various reagents have had enough time to take effect but not too long to maintain the desired effect. Because current methods of emulsifying ASA do not optimally feed the emulsion into a product stream and because they do not efficiently address the two requirements inherent with ASA emulsions, there remains a need for an improved method of producing ASA emulsions and efficiently introducing them into the papermaking process.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.